The present invention relates to a frame for a window, said frame being intended to serve either as a stationary frame or as a sash frame and comprising a top member, a bottom ember and two side members, each having a side surface intended to face a corresponding side surface of another frame of the window. It further relates to a window with such a frame and to a method of making a frame.
In this, whenever the term “frame” is used it is to be understood as including both sash frames carrying panes and stationary frames carrying sash frames. The terms “sash frame” and “stationary frame” are used when reference is made specifically to frames intended for one of these two purposes.
Frames for windows are traditionally made from wooden members, from moulded polyurethane members with a wooden core for reinforcement or from extruded members of aluminum or polyvinylchloride. Different components such as hinges, locking assemblies and gaskets are added to provide the needed functionality and when using extruded profiles, insulation material may be provided in hollows in the profile.
With these ways of making a frame, a limit on the thermal properties seems to have been reached, but the demand for still more energy efficient windows keeps rising.